Project Summary/Abstract Rural areas of the western U.S. experience an increased burden and disparities in children's respiratory health compared to urban centers. Of particular concern in the western U.S. are more intense wildfires, which increase air pollution in surrounding areas and affect regional air quality. Assessing lower respiratory tract infection (LRTI) risk in some areas of the west is also complicated by complex topography, which creates steep air quality gradients during inversion events common in both winter and summer. A comprehensive understanding of the mechanisms underlying LRTI epidemics among neglected at-risk populations at the rural state level, such as Montana, is poor. Thus a thorough investigation of the multidimensional socio- demographic-climate-pollution processes affecting children's respiratory health must be conducted in order to improve adequate policy and public health actions to address both current and future climate-pollution challenges. We will gather multiple data sources, including novel wildfire-induced exposure and inversion prone layers, in order to describe the distribution, timing and intensity of respiratory infections unique to Montana's children (Aim 1). We will develop three independent, rigorous, and scientifically-defensible modeling frameworks to help identify the causal drivers of LRTIs among children in Montana (Aim 2). Finally, we will develop a Montana LRTI risk index that can be used as an indicator for current risk within Montana and a means to measure progress, analyze trends, and quantify uncertainty in LRTI risk for Montana's public. Our combined mapping and surveillance platform, data assimilation and multi-modeling approach, and LRTI risk assessment index will greatly help the identification of public health threats of LRTIs among Montana's children. Ultimately, the results we will generate will inform interventions to mitigate LRTI among children in MT. As an intermediate step, the findings from this project will be used to leverage and design an expanded study of LRTI throughout the western U.S.